JP2011075783A - Fixing apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing apparatus capable of reducing the influence of a second fixing portion on the surface of an image while employing a simple structure, or an image forming apparatus capable of forming a favorable image. <P>SOLUTION: The fixing apparatus includes: a first fixing portion 91 including a first heating portion 91a that heats transfer material onto which an image has been transferred and a first pressure portion 91b that forms a first nip by pressing against the first heating portion 91a; the second fixing portion 92 including a second heating portion 92a that heats the transfer material S that has undergone fixing in the first fixing portion 91 and a second pressure portion 92b that forms a second nip by pressing against the second heating portion 92a; and a fixing portion suction guide 300 including a suction surface 302 sucking the transfer material S that has undergone fixing in the first fixing portion 91 vertically upward with a surface of the transfer material S onto which the image has been transferred facing vertically downward, wherein an end of the suction surface 302 on a side toward the second fixing portion 92 in a transport direction of the transfer material S is located higher in a vertical direction than an imaginary line H that connects the first nip and the second nip. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fixing device and an image forming apparatus related to electrophotography.

  Conventionally, as a fixing unit of an image forming apparatus, a first fixing unit that fixes an image transferred to a transfer material, a second fixing unit that performs fixing after the first fixing, and a transfer material that has passed through the first fixing unit are a first fixing unit. 2 discloses a bypass conveyance path that does not pass through a fixing unit (Patent Document 1).

JP 2006-308889 A

  However, since the image forming apparatus disclosed in Patent Document 1 includes a curling unit that corrects curl caused by thermal contraction of toner and a flapper that switches a conveyance path, the apparatus is enlarged and complicated.

  In addition, after the transfer material is discharged from the first fixing unit, the printing surface may hang down in the vertical direction due to the influence of gravity, and the print surface may collide with the second fixing unit to cause an image defect. Furthermore, when a roller or a flapper touches a high-temperature image surface immediately after fixing, the gloss of the contacted image portion may be different from other portions, and the image quality may be deteriorated.

  In order to solve the above problems, the present invention provides a fixing device capable of reducing the influence on the image surface by the second fixing unit with a simple structure, and forming a good image. An object of the present invention is to provide an image forming apparatus capable of performing the above.

  The fixing device of the present invention includes a first fixing unit having a first heating unit that heats a transfer material onto which an image has been transferred, and a first pressure unit that presses the first heating unit to form a first nip portion. A second heating unit that heats the transfer material fixed by the first fixing unit, and a second pressing unit that presses against the second heating unit to form a second nip portion. And a suction surface for sucking the transfer material fixed by the first fixing unit upward in the vertical direction toward the lower side in the vertical direction, and in the conveying direction of the transfer material. A fixing unit suction guide in which an end portion on the second fixing unit side of the suction surface is arranged above the imaginary line connecting the first nip unit and the second nip unit in the vertical direction. It is characterized by.

  The image forming apparatus of the present invention includes a latent image carrier on which a latent image is formed, a developing unit that develops the latent image on the latent image carrier with a liquid developer containing toner particles and a carrier liquid, and the development A transfer medium on which the developed image is transferred onto the latent image carrier, a transfer roller that contacts the transfer medium to form a transfer nip, and transfers the image onto a transfer material; and the image is transferred A first fixing unit having a first heating unit that heats the transferred transfer material, a first pressing unit that presses the first heating unit to form a first nip portion, and fixing by the first fixing unit. A second fixing unit having a second heating unit that heats the transferred transfer material, a second pressing unit that presses against the second heating unit to form a second nip portion, and fixing by the first fixing unit The transferred image is sucked upward in the vertical direction with the surface on which the image is transferred facing downward in the vertical direction. An end on the second fixing unit side of the suction surface is located above the imaginary line connecting the first nip portion and the second nip portion in the conveyance direction of the transfer material. And a fixing unit suction guide disposed on the head.

  The first fixing unit side of the suction surface is parallel or substantially parallel to the virtual line.

  The first fixing unit is a heating roller in which the first heating unit has an elastic layer, and the first pressing unit has a pressure roller whose surface hardness is the same as or substantially the same as the surface hardness of the heating roller. It is.

  Further, the first fixing unit side of the suction surface is inclined downward in the vertical direction from the virtual line.

  A conveying belt that forms the suction surface and conveys the transfer material fixed by the first fixing unit; a driving roller that wraps the conveying belt to drive the conveying belt; and the conveying belt And a driven roller for winding.

  Moreover, the said conveyance belt has a hole which lets airflow pass.

  According to the fixing device of the present invention, it is possible to reduce the influence of the second fixing unit on the image surface with a simple structure. Further, according to the image forming apparatus of the present invention, it is possible to reduce the influence of the second fixing unit on the image surface with a simple structure, and it is possible to form a good image.

  In addition, the end of the suction surface on the second fixing unit side is arranged above the vertical direction with respect to a virtual line connecting the first nip portion and the second nip portion in the conveyance direction of the transfer material. Since the fixing portion suction guide is provided, the transfer material can smoothly move to the nip portion of the second fixing roller pair.

  Further, since the first fixing portion side of the suction surface is parallel or substantially parallel to the virtual line, the transfer material can smoothly move to the fixing portion suction guide.

  In addition, since the first fixing unit side of the suction surface is inclined downward in the vertical direction from the imaginary line, the transfer material can smoothly move to the fixing unit suction guide.

  A conveying belt that forms the suction surface and conveys the transfer material fixed by the first fixing unit; a driving roller that wraps the conveying belt to drive the conveying belt; and the conveying belt Since the transfer material sticks to the fixing unit conveying belt and the transfer material and the fixing unit conveying belt move together, the second fixing roller pair from the first fixing roller pair side is provided. It becomes possible to stably convey the transfer material to the side.

  In addition, since the fixing unit conveyance belt has holes through which airflow passes, the transfer material can be conveyed more stably.

1 is a diagram illustrating a first embodiment of an image forming apparatus. It is a figure which shows the fixing | fixed part suction guide of 1st Embodiment. It is a figure which shows the fixing | fixed part suction guide of 2nd Embodiment. It is an enlarged view of the first fixing roller pair of the second embodiment and the third embodiment. It is a figure which shows the fixing | fixed part suction guide of 3rd Embodiment. It is a figure which shows the fixing | fixed part suction guide of 4th Embodiment. FIG. 10 is a diagram illustrating a fixing unit suction guide according to a fifth embodiment. FIG. 10 is an enlarged view of a first fixing roller pair according to a fourth embodiment and a fifth embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing main components constituting the image forming apparatus according to the first embodiment of the present invention. Developing devices 30Y, 30M, 30C, and 30K as developing units are arranged below the image forming device and are used as transfer units with respect to the intermediate transfer belt 40 as a transfer medium arranged at the center of the image forming device. The configurations of the secondary transfer unit 60 and the fixing unit 90 as a fixing unit are arranged in the upper part of the image forming apparatus. In particular, since the fixing unit 90 is laid out above the intermediate transfer belt 40, the installation area of the entire image forming apparatus can be suppressed.

  First, the peripheral portion of the photoreceptor will be described. The peripheral portions of the photoreceptors 10Y, 10M, 10C, and 10K as latent image carriers made of a cylindrical member having a photosensitive layer such as an amorphous silicon photoreceptor on the outer peripheral surface are the photoreceptors 10Y, 10M, 10C, and 10K. Development as a developer carrier of the exposure units 12Y, 12M, 12C, and 12K, and the developing devices 30Y, 30M, 30C, and 30K with reference to the corona chargers 11Y, 11M, 11C, and 11K Rollers 20Y, 20M, 20C, 20K, first photoconductor squeeze rollers 13Y, 13M, 13C, 13K, second photoconductor squeeze rollers 13Y ′, 13M ′, 13C ′, 13K ′, primary transfer portions 50Y, 50M, 50C, 50K, static elimination unit (not shown) and photoconductor cleaning blades 18Y, 18M, 18C, 18K are arranged. It is. In the image forming process, the configuration arranged in the preceding stage in the order of the corona chargers 11Y, 11M, 11C, and 11K to the photosensitive member cleaning blades 18Y, 18M, 18C, and 18K is upstream of the configuration arranged in the subsequent stage. Defined as something.

  In the peripheral area of the photoconductor, first, the photoconductors 10Y, 10M, 10C, and 10K are arranged upstream of the nip portion between the photoconductors 10Y, 10M, 10C, and 10K and the developing rollers 20Y, 20M, 20C, and 20K in the rotation direction of the photoconductors 10Y, 10M, 10C, and 10K. The photoconductors 10Y, 10M, 10C, and 10K are uniformly charged by the corona chargers 11Y, 11M, 11C, and 11K. Next, it is input by exposure units 12Y, 12M, 12C, and 12K disposed downstream from the corona chargers 11Y, 11M, 11C, and 11K and upstream from the nip portion with the developing rollers 20Y, 20M, 20C, and 20K. Exposure is performed on the basis of the image signal, and light is irradiated onto the charged photoreceptors 10Y, 10M, 10C, and 10K to form an electrostatic latent image.

  Next, the developing devices 30Y, 30M, 30C, and 30K will be described. In the developing devices 30Y, 30M, 30C, and 30K, the augers 34Y, 34M, 34C, and 34K that stir and convey the liquid developer in the developer containers 31Y, 31M, 31C, and 31K that store the liquid developers of the respective colors supply the developer. The liquid developer is supplied to the anilox rollers 32Y, 32M, 32C, and 32K as members. Next, the anilox rollers 32Y, 32M, 32C, and 32K apply the liquid developer of each color whose amount is regulated by the regulating blades 33Y, 33M, 33C, and 33K to the developing rollers 20Y, 20M, 20C, and 20K.

  The liquid developer carried on the developing rollers 20Y, 20M, 20C, and 20K is compacted by the compaction corona generators 22Y, 22M, 22C, and 22K, and then formed on the photoreceptors 10Y, 10M, 10C, and 10K. The electrostatic latent image thus developed is developed to form toner images on the photoreceptors 10Y, 10M, 10C, and 10K. The liquid developer remaining on the developing rollers 20Y, 20M, 20C, and 20K is cleaned by the developing roller cleaning blades 21Y, 21M, 21C, and 21K.

  The liquid developer contained in the developer container 31Y is a low-concentration (about 1 to 3 wt%) and low-viscosity volatile at room temperature using a conventionally used Isopar (trademark: exon) as a carrier. Is a non-volatile liquid developer having a high concentration and high viscosity and having non-volatility at room temperature. That is, in the liquid developer in the present invention, a solid having an average particle diameter of 1 μm in which a colorant such as a pigment is dispersed in a thermoplastic resin is introduced into a liquid solvent such as an organic solvent, silicon oil, mineral oil, or edible oil. High viscosity (HAAKE RheoStress RS600, which is added together with a dispersant and has a toner solid content concentration of about 15 to 25%, and has a viscoelasticity of 30 to 30 at a shear rate of 1000 (1 / s) at 25 ° C. (About 300 mPa · s).

  The toner images formed on the photoreceptors 10Y, 10M, 10C, and 10K are fed by the first photoreceptor squeeze rollers 13Y, 13M, 13C, and 13K and the second photoreceptor squeeze rollers 13Y ′, 13M ′, 13C ′, and 13K ′. Squeezed.

  The intermediate transfer belt 40 is a belt formed of a seamless elastic member such as rubber, and is stretched between a belt driving roller 41 and a tension roller 42, and the primary transfer portions 50Y, 50M, 50C, and 50K, and the photoreceptor 10Y. The belt drive roller 41 is rotationally driven while abutting 10M, 10C, and 10K. The primary transfer portions 50Y, 50M, 50C, and 50K are arranged such that the primary transfer rollers 51Y, 51M, 51C, and 51K are opposed to each other with the photoreceptors 10Y, 10M, 10C, and 10K and the intermediate transfer belt 40 interposed therebetween. The developed toner images of the respective colors on the photoreceptors 10Y, 10M, 10C, and 10K are sequentially superimposed and transferred onto the intermediate transfer belt 40 using the contact position with 10M, 10C, and 10K as a transfer position, and a full-color toner image is transferred. Form.

  After passing through the primary transfer portions 50Y, 50M, 50C, and 50K, the liquid developer remaining on the photoreceptors 10Y, 10M, 10C, and 10K is removed by a charge removal unit (not shown) or the photoreceptor cleaning blades 18Y, 18M, 18C, and 18K. Is removed.

  Note that the arrangement order of members such as the photoconductors and developing devices corresponding to the respective colors Y, M, C, and K is not limited to the example illustrated in FIG. 1 and can be arbitrarily set.

  Next, transfer of the toner image on the intermediate transfer belt 40 to the transfer material S will be described.

  The transfer material S is supplied to the image forming apparatus by a paper feeding device. The transfer material S set in the first paper feed tray 101a or the second paper feed tray 101b is fed and conveyed by the first paper feed roller 102a or the second paper feed roller 102b one by one at a predetermined timing. It is transported to the route La. In the transfer material conveyance path Lab, the transfer material S is conveyed to the secondary transfer position by the gate roller pairs 104 and 104 ′ and the transfer material guide 105.

  The secondary transfer unit 60 includes a secondary transfer roller 61 as a transfer member and a secondary transfer roller cleaning blade 85 that cleans the secondary transfer roller 61. The secondary transfer roller 61 rotates in the direction indicated by the arrow as the belt driving roller 41 rotates, and a transfer bias is applied.

  The transfer material S conveyed from the transfer material guide 105 is seated with a gripper 64 and a gripper 64 serving as a transfer material gripping portion disposed in a concave portion 63 whose tip is extended in the axial direction of the secondary transfer roller 61. It is gripped by a gripper support portion 65 as a transfer material gripping portion receiving portion to be positioned with respect to the transfer roller 61, and reliably moves toward the transfer nip as the transfer roller 61 rotates.

  The toner image on the intermediate transfer belt 40 is transferred to a transfer material S such as paper, film, or cloth at a transfer nip. When the grip portion of the gripper 64 and the leading end portion of the transfer material S pass through the transfer nip, the gripper 64 starts to move away from the claw seat 65, and the leading end portion of the transfer material S is released. Next, with further rotation of the transfer roller 61, the protrusion claw 79 is set at the protrusion position, and the transfer material S is peeled from the transfer roller 61.

  On the other hand, the transfer material S released from gripping by the gripper 64 is air from the blower 400 that discharges the air from the opening 402 of the housing 401 generated by the operation of the airflow generator 405 as indicated by the arrow A. By spraying, it is lightly pressed against the transfer roller 61 side, and is pressed in a direction away from the transfer roller 61 by the protruding claw 79.

  Thus, the transfer material S sandwiched between the belt drive roller 41 and the transfer roller 61 is transferred to the transfer material conveying means 200 by further rotation of the belt drive roller 41 and the transfer roller 61 in order from the front end to the rear end. Moving. That is, the transfer end portion of the transfer material S is peeled off while the toner image on the intermediate transfer belt 40 is secondarily transferred to the transfer material S.

  With such a configuration, it is possible to prevent the transfer material S from being soiled by touching the intermediate transfer belt 40 or the like when the rear end portion of the transfer material S is discharged from the secondary transfer nip. In the case of the transfer material S having a small elastic restoring force and a weak waist, the air blowing of the blower 400 can be omitted.

  Next, the conveyance of the transfer material S after the secondary transfer will be described.

  A first suction device 210, a transfer material transport device 230, and a second suction device 270 are sequentially arranged as the transfer material transport means 200 downstream of the secondary transfer unit 60 in the transfer material transport path Lab. Is conveyed to the fixing unit 90.

  The transfer material S after the secondary transfer is held on the suction surface 212 without dropping due to the suction force B from the suction surface 212 of the housing portion 211 generated in accordance with the operation of the air flow generation unit 215 of the first suction device 210. On the other hand, the suction surface 212 is conveyed by the force of the feeding operation from the secondary transfer unit 60 side.

  The transfer material S conveyed on the suction surface 212 of the first suction device 210 under the force of the feeding operation from the secondary transfer unit 60 side reaches the transfer material conveyance device 230 side. Next, the transfer material S is held on the transport surface by the suction force C from the suction surface 232 of the housing portion 231 generated in accordance with the operation of the airflow generation unit 235 of the transfer material transport device 230. At the same time, the transfer material S is moved by the transfer material conveying member driving roller 251 and the transfer material conveying member 250 wound around the transfer material conveying member driving roller 251 and the transfer material conveying member stretching rollers 252 and 253 is moved. As the operation proceeds, the conveyance surface advances toward the fixing unit 90.

  The transfer material S transported on the transport surface of the transfer material transport device 230 is sucked and transported by the suction force D from the suction surface 272 of the housing portion 271 generated in accordance with the operation of the air flow generation unit 275 of the second suction device 270. Is done.

  Next, fixing of the toner image to the transfer material S will be described.

  In the fixing unit 90, a single color toner image or a full color toner image transferred onto the transfer material S such as paper is fused and fixed to the transfer material S such as paper.

  The fixing unit 90 includes a first fixing roller pair 91 as a first fixing unit, and a second fixing roller pair 92 as a second fixing unit on the downstream side of the first fixing roller pair 91. The first fixing roller pair 91 includes a first heating roller 91a as a first heating unit having a heater therein, and a first pressure unit as a first pressure unit urged with a predetermined pressure toward the first heating roller 91a. A pressure roller 91b, and a transfer material S is inserted between the nips, and a single-color toner image or a full-color toner image transferred onto the transfer material S is fused to the transfer material S such as paper. Let it settle. Similarly, the second fixing roller pair 92 includes a second heating roller 92a as a second heating unit having a heater therein, and a second pressure unit urged with a predetermined pressure toward the second heating roller 92a. And a second color roller 92b, and a transfer material S is inserted between the nips, and a single color toner image or a full color toner image transferred onto the transfer material S is transferred to a transfer material S such as paper. Fusing and fixing firmly.

  Further, a fixing unit suction guide 300 is disposed between the first fixing roller pair 91 and the second fixing roller pair 92 of the fixing unit 90. The fixing unit suction guide 300 is disposed on the opposite side of the housing 301, the fixing unit suction surface 302 disposed on the transfer material transport path Lab side of the housing 301, and the transfer material transport path Lab of the housing 301. The transfer material S does not fall by the suction force E from the fixing portion suction surface 302 of the housing portion 301 generated by the operation of the airflow generation portion 305. While being held by the surface 302, it is conveyed along the fixing unit suction surface 302 to the second fixing roller pair 92 side by the force of the feeding operation from the first fixing roller pair 91.

  After the fixing, in the case of single-sided printing, the transfer material S is transported to the discharge transport path Lc and discharged.

  In the case of duplex printing, the transfer material S is guided by the first flapper 121 and conveyed to the first duplex conveyance path Lb1. Thereafter, in the second duplex conveyance path Lb2 having the first reverse conveyance roller pair 111, 111 ′, the second reverse conveyance roller pair 112, 112 ′, and the third reverse conveyance roller pair 113, 113 ′, the conveyance direction is reversed, It is guided by the second flapper 122 and conveyed to the third double-sided conveyance path Lb3.

  In the third double-sided conveyance path Lb3, the transfer material S passes through a pair of curling rollers 114 and 114 ′ serving as a curling unit, and a pair of first double-sided conveyance rollers 115 and 115 ′ and a pair of second double-sided conveyance rollers 116 and 116 ′. , The third double-sided conveyance roller pair 117, 117 ′ and the fourth double-sided conveyance roller pair 118, 118 ′. Next, the transfer material S reversed from the pair of gate rollers 104 and 104 ′ and the transfer material guide 105 is conveyed to the transfer material conveyance path Lab. Thereafter, the transfer material S passes through the fixing unit 90, is transported to the discharge transport path Lc, and is discharged.

  Hereinafter, the fixing unit 90 will be described in detail.

  The first heating roller 91a and the second heating roller 92a of the first embodiment have a diameter of 60 mm, the thickness of the core metal is 2 mm, and the core metal is made of aluminum, iron, stainless steel, brass, or the like. An elastic layer is formed around the cored bar. The elastic layer has a thickness of 2 mm, and the elastic layer is made of silicon rubber, fluorine rubber, urethane rubber, or the like. Further, a release layer is formed around the elastic layer. The release layer has a thickness of 30 μm, and the release layer is made of PFA, PTFE, FEP, ETFE or the like.

  The first pressure roller 91b and the second pressure roller 92b of the first embodiment have a diameter of 60 mm, the thickness of the core metal is 2 mm, and the core metal is made of aluminum, iron, stainless steel, brass, or the like. An elastic layer is formed around the cored bar. The elastic layer has a thickness of 2 mm, and the elastic layer is made of silicon rubber, fluorine rubber, urethane rubber, or the like. Further, a release layer is formed around the elastic layer. The release layer has a thickness of 30 μm, and the release layer is made of PFA, PTFE, FEP, ETFE or the like.

  Moreover, the 1st heating roller 91a and the 2nd heating roller 92a are driven by the drive member which is not illustrated, and the 1st pressure roller 91b and the 2nd pressure roller 92b are the 1st heating roller 91a and the 2nd heating roller 92a, respectively. Rotates following the rotation.

  The first pressure roller 91b and the second pressure roller 92b are made of a hard material such as iron, aluminum, stainless steel, and brass, and the first heating roller 91a and the second heating roller 92a are made of silicon rubber, urethane rubber, natural rubber, or the like. When a soft material such as a rubber layer or a sponge layer such as silicon sponge, urethane sponge, or melamine sponge is provided on the shaft, it is possible to correct the curl to the image surface side caused by heat. Further, the second heating roller 92a and the second pressure roller 92b do not need to be completely separated from each other, and may be formed so as to reduce the applied pressure in addition to the case where they are completely separated.

  Next, the fixing unit suction guide 300 will be described in detail. The fixing unit suction guide 300 according to the present embodiment is configured such that the first fixing roller suction guide 300 has an imaginary line H connecting the first nip portion of the first fixing roller pair 91 and the second nip portion of the second fixing roller pair 92. The two fixing roller pair 92 side is arranged above the vertical direction.

  FIG. 2 is a diagram illustrating the fixing unit suction guide 300 according to the first embodiment.

  The fixing unit suction guide 300 of the first embodiment includes a housing 301, a fixing unit suction surface 302 disposed on the transfer material transport path Lab side of the housing 301, and a transfer material transport path Lab of the housing 301. The airflow generating unit 305, the fixing unit conveyance belt 310, and the driving shaft 311 and the driven shaft 312 that wrap around the fixing unit conveyance belt 310 are provided on the opposite side.

  The fixing unit suction guide 300 is held on the fixing unit suction surface 302 without falling by the suction force from the fixing unit suction surface 302 of the housing unit 301 generated by the operation of the airflow generation unit 305. When the drive shaft 311 is driven by a driving unit (not shown), the fixing unit conveyance belt 310 is rotated and conveyed to the second fixing roller pair 92 side along the fixing unit suction surface 302.

  The fixing unit suction guide 300 includes a second fixing roller pair of the fixing unit suction guide 300 with respect to a virtual line H connecting the first nip portion of the first fixing roller pair 91 and the second nip portion of the second fixing roller pair 92. The 92 side is arranged above the vertical direction. In the first embodiment, it is inclined from about 5 ° to 30 ° with respect to the horizontal line.

  Further, the fixing unit conveyance belt 310 has a hole through which air passes, and moves along the fixing unit suction surface 302.

  By using the fixing unit suction guide 300 in this way, the moisture content of the transfer material S is rapidly reduced by exposing the transfer material S to a large amount of air, and curling can be corrected. For this reason, there is no need to provide a conventional curl roller pair, and the image forming apparatus can be downsized. Further, since the fixing unit suction guide 300 sucks the transfer material S, it is possible to reduce the collision between the front end of the transfer material S and the second heating roller 92a.

  In addition, the fixing unit suction guide 300 is configured such that the second fixing of the fixing unit suction guide 300 with respect to an imaginary line H connecting the first nip portion of the first fixing roller pair 91 and the second nip portion of the second fixing roller pair 92. Since the roller pair 92 side is arranged upward in the vertical direction, even if the transfer material S is discharged from the fixing unit suction guide 300 and then droops downward in the vertical direction due to the influence of gravity, the printing surface is the second heating roller 92a. It is possible to set the non-printing surface to come into contact with the second pressure roller 92b first before the collision with the image, and it is possible to reduce image defects.

  FIG. 3 is a diagram illustrating a fixing unit suction guide 300 according to the second embodiment.

  The fixing unit suction guide 300 according to the second embodiment includes a first housing unit 301a, a first fixing unit suction surface 302a disposed on the transfer material transport path Lab side of the first housing unit 301a, and a first housing unit 301a. The first airflow generating unit 305a, the second housing unit 301b, and the second fixing unit disposed on the transfer material transporting path Lab side of the second housing unit 301b disposed on the opposite side of the transfer material transporting path Lab. Drive for rotating the part suction surface 302b, the second airflow generation part 305b disposed on the opposite side of the transfer material transport path Lab of the second housing part 301b, the fixing part transport belt 310, and the fixing part transport belt 310 The shaft 311 and the first driven shaft 312 and the second driven shaft 313 disposed between the first housing portion 301a and the second housing portion 301b are provided.

  The fixing unit suction guide 300 includes a first fixing unit suction surface 302a of the first casing unit 301a and a second fixing unit of the second casing unit 301b that are generated in accordance with the operations of the first air flow generation unit 305a and the second air flow generation unit 305b. The transfer material S is held on the first fixing unit suction surface 302a and the second fixing unit suction surface 302b without dropping by the suction force from the suction surface 302b, and the drive shaft 311 is driven by a driving unit (not shown). As a result, the fixing unit conveyance belt 310 is rotated and conveyed to the second fixing roller pair 92 side along the first fixing unit suction surface 302a and the second fixing unit suction surface 302b.

  The fixing unit suction guide 300 includes a second fixing roller pair of the fixing unit suction guide 300 with respect to a virtual line H connecting the first nip portion of the first fixing roller pair 91 and the second nip portion of the second fixing roller pair 92. The 92 side is arranged above the vertical direction. In the second embodiment, as shown in FIG. 4, the first fixing unit suction surface 302a on the first fixing roller pair 91 side is formed horizontally, and the second fixing unit suction surface 302b on the second fixing roller pair 92 side is formed. It is formed so as to be inclined and to be above the vertical direction.

  Further, the fixing unit conveyance belt 310 has a hole through which air passes, and moves along the fixing unit suction surface 302.

  By using the fixing unit suction guide 300 in this way, the moisture content of the transfer material S is rapidly reduced by exposing the transfer material S to a large amount of air, and curling can be corrected. For this reason, there is no need to provide a conventional curl roller pair, and the image forming apparatus can be downsized. Further, since the fixing unit suction guide 300 sucks the transfer material S, it is possible to reduce the collision between the front end of the transfer material S and the second heating roller 92a.

  In addition, the fixing unit suction guide 300 is configured such that the second fixing of the fixing unit suction guide 300 with respect to an imaginary line H connecting the first nip portion of the first fixing roller pair 91 and the second nip portion of the second fixing roller pair 92. Since the roller pair 92 side is arranged upward in the vertical direction, even if the transfer material S is discharged from the fixing unit suction guide 300 and then droops downward in the vertical direction due to the influence of gravity, the printing surface is the second heating roller 92a. It is possible to set the non-printing surface to come into contact with the second pressure roller 92b first before the collision with the image, and it is possible to reduce image defects.

  FIG. 5 is a diagram illustrating a fixing unit suction guide 300 according to the third embodiment.

  The fixing unit suction guide 300 according to the third embodiment includes a housing 301, a fixing unit suction surface 302 disposed on the transfer material transport path Lab side of the housing 301, and a transfer material transport path Lab of the housing 301. And an airflow generation unit 305 disposed on the opposite side.

  The fixing unit suction guide 300 is held on the fixing unit suction surface 302 without falling by the suction force from the fixing unit suction surface 302 of the housing unit 301 generated by the operation of the airflow generation unit 305. By the rotation of the first fixing roller pair 91, the first fixing roller pair 91 is conveyed along the fixing unit suction surface 302 to the second fixing roller pair 92 side.

  The fixing unit suction guide 300 includes a second fixing roller pair of the fixing unit suction guide 300 with respect to a virtual line H connecting the first nip portion of the first fixing roller pair 91 and the second nip portion of the second fixing roller pair 92. The 92 side is arranged above the vertical direction. In the third embodiment, as in the second embodiment, as shown in FIG. 4, the first fixing unit suction surface 302 on the first fixing roller pair 91 side is formed horizontally, and the second fixing roller pair 92 side first is formed. (2) The fixing unit suction surface 302 is formed so as to be inclined upward in the vertical direction.

  By using the fixing unit suction guide 300 in this way, the moisture content of the transfer material S is rapidly reduced by exposing the transfer material S to a large amount of air, and curling can be corrected. For this reason, there is no need to provide a conventional curl roller pair, and the image forming apparatus can be downsized. Further, since the fixing unit suction guide 300 sucks the transfer material S, it is possible to reduce the collision between the front end of the transfer material S and the second heating roller 92a.

  In addition, the fixing unit suction guide 300 is configured such that the second fixing of the fixing unit suction guide 300 with respect to an imaginary line H connecting the first nip portion of the first fixing roller pair 91 and the second nip portion of the second fixing roller pair 92. Since the roller pair 92 side is arranged upward in the vertical direction, even if the transfer material S is discharged from the fixing unit suction guide 300 and then droops downward in the vertical direction due to the influence of gravity, the printing surface is the second heating roller 92a. It is possible to set the non-printing surface to come into contact with the second pressure roller 92b first before the collision with the image, and it is possible to reduce image defects.

  The first heating roller 91a and the first pressure roller 91b of the second embodiment and the third embodiment have a diameter of 60 mm, the thickness of the core metal is 2 mm, and the material of the core metal is aluminum, iron, stainless steel, brass, etc. Consists of. An elastic layer is formed around the cored bar. The elastic layer has a thickness of 2 mm, and the elastic layer is made of silicon rubber, fluorine rubber, urethane rubber, or the like. Further, a release layer is formed around the elastic layer. The release layer has a thickness of 30 μm, and the release layer is made of PFA, PTFE, FEP, ETFE or the like. The roller hardness is Asker-C 20 °.

  The first heating roller 91a and the first pressure roller 91b have the same or substantially the same hardness, and the first nip portion formed by the first heating roller 91a and the first pressure roller 91b is shown in FIG. As shown, a horizontal nip substantially perpendicular to the line C connecting the center lines of the first heating roller 91a and the first pressure roller 91b is formed. The distance between the extension line of the horizontal nip and the fixing unit suction surface 302 is about 0 to 5 mm. The first heating roller 91a and the first pressure roller 91b are in pressure contact with a load of 10 to 80 kgf. Here, the same or substantially the same hardness is a range of ± 5 degrees in Asker C hardness.

  FIG. 6 is a diagram illustrating a fixing unit suction guide 300 according to the fourth embodiment.

  The fixing unit suction guide 300 according to the fourth embodiment includes a first casing 301a, a first fixing unit suction surface 302a disposed on the transfer material transport path Lab side of the first casing 301a, and a first casing 301a. The first airflow generating unit 305a, the second housing unit 301b, and the second fixing unit disposed on the transfer material transporting path Lab side of the second housing unit 301b disposed on the opposite side of the transfer material transporting path Lab. Drive for rotating the part suction surface 302b, the second airflow generation part 305b disposed on the opposite side of the transfer material transport path Lab of the second housing part 301b, the fixing part transport belt 310, and the fixing part transport belt 310 The shaft 311 and the first driven shaft 312 and the second driven shaft 313 disposed between the first housing portion 301a and the second housing portion 301b are provided.

  The fixing unit suction guide 300 includes a first fixing unit suction surface 302a of the first casing unit 301a and a second fixing unit of the second casing unit 301b that are generated in accordance with the operations of the first air flow generation unit 305a and the second air flow generation unit 305b. The transfer material S is held on the first fixing unit suction surface 302a and the second fixing unit suction surface 302b without dropping by the suction force from the suction surface 302b, and the drive shaft 311 is driven by a driving unit (not shown). As a result, the fixing unit conveyance belt 310 is rotated and conveyed to the second fixing roller pair 92 side along the first fixing unit suction surface 302a and the second fixing unit suction surface 302b.

  The fixing unit suction guide 300 includes a second fixing roller pair of the fixing unit suction guide 300 with respect to a virtual line H connecting the first nip portion of the first fixing roller pair 91 and the second nip portion of the second fixing roller pair 92. The 92 side is arranged above the vertical direction. In the fourth embodiment, the first fixing unit suction surface 302a on the first fixing roller pair 91 side is formed so as to be inclined downward on the printing surface side in the vertical direction, and the second fixing roller pair 92 side second. The fixing unit suction surface 302b is inclined to the opposite side to the printing surface so as to be upward in the vertical direction.

  Further, the fixing unit conveyance belt 310 has a hole through which air passes, and moves along the fixing unit suction surface 302.

  By using the fixing unit suction guide 300 in this way, the moisture content of the transfer material S is rapidly reduced by exposing the transfer material S to a large amount of air, and curling can be corrected. For this reason, there is no need to provide a conventional curl roller pair, and the image forming apparatus can be downsized. Further, since the fixing unit suction guide 300 sucks the transfer material S, it is possible to reduce the collision between the front end of the transfer material S and the second heating roller 92a.

  In addition, the fixing unit suction guide 300 is configured such that the second fixing of the fixing unit suction guide 300 with respect to an imaginary line H connecting the first nip portion of the first fixing roller pair 91 and the second nip portion of the second fixing roller pair 92. Since the roller pair 92 side is arranged upward in the vertical direction, even if the transfer material S is discharged from the fixing unit suction guide 300 and then droops downward in the vertical direction due to the influence of gravity, the printing surface is the second heating roller 92a. It is possible to set the non-printing surface to come into contact with the second pressure roller 92b first before the collision with the image, and it is possible to reduce image defects.

  FIG. 7 is a diagram illustrating a fixing unit suction guide 300 according to the fifth embodiment.

  The fixing unit suction guide 300 of the fifth embodiment includes a housing 301, a fixing unit suction surface 302 disposed on the transfer material transport path Lab side of the housing 301, and a transfer material transport path Lab of the housing 301. And an airflow generation unit 305 disposed on the opposite side.

  The fixing unit suction guide 300 is held on the fixing unit suction surface 302 without falling by the suction force from the fixing unit suction surface 302 of the housing unit 301 generated by the operation of the airflow generation unit 305. By the rotation of the first fixing roller pair 91, the first fixing roller pair 91 is conveyed along the fixing unit suction surface 302 to the second fixing roller pair 92 side.

  The fixing unit suction guide 300 includes a second fixing roller pair of the fixing unit suction guide 300 with respect to a virtual line H connecting the first nip portion of the first fixing roller pair 91 and the second nip portion of the second fixing roller pair 92. The 92 side is arranged above the vertical direction. In the fifth embodiment, the first fixing unit suction surface 302a on the first fixing roller pair 91 side is formed so as to be inclined downward on the printing surface side in the vertical direction, and the second fixing roller pair 92 side second. The fixing unit suction surface 302b is inclined to the opposite side to the printing surface so as to be upward in the vertical direction.

  By using the fixing unit suction guide 300 in this way, the moisture content of the transfer material S is rapidly reduced by exposing the transfer material S to a large amount of air, and curling can be corrected. For this reason, there is no need to provide a conventional curl roller pair, and the image forming apparatus can be downsized. Further, since the fixing unit suction guide 300 sucks the transfer material S, it is possible to reduce the collision between the front end of the transfer material S and the second heating roller 92a.

  In addition, the fixing unit suction guide 300 is configured such that the second fixing of the fixing unit suction guide 300 with respect to an imaginary line H connecting the first nip portion of the first fixing roller pair 91 and the second nip portion of the second fixing roller pair 92. Since the roller pair 92 side is arranged upward in the vertical direction, even if the transfer material S is discharged from the fixing unit suction guide 300 and then droops downward in the vertical direction due to the influence of gravity, the printing surface is the second heating roller 92a. It is possible to set the non-printing surface to come into contact with the second pressure roller 92b first before the collision with the image, and it is possible to reduce image defects.

  The first heating roller 91a of the fourth embodiment and the fifth embodiment has a diameter of 60 mm, the thickness of the cored bar is 2 mm, and the material of the cored bar is made of aluminum, iron, stainless steel, brass, or the like. An elastic layer is formed around the cored bar. The elastic layer has a thickness of 2 mm, and the elastic layer is made of silicon rubber, fluorine rubber, urethane rubber, or the like. Further, a release layer is formed around the elastic layer. The release layer has a thickness of 30 μm, and the release layer is made of PFA, PTFE, FEP, ETFE or the like. The roller hardness is Asker-C 20 °.

  In the first pressure roller 91b of the fourth embodiment and the fifth embodiment, the elastic layer has a thickness of 5 mm, and the others are the same as the first heating roller 91a.

  Further, as in the fourth and fifth embodiments, when the roller hardness of the first heating roller 91a is larger than the roller hardness of the first pressure roller 91b, the first heating roller 91a and the first pressure roller 91b The first nip portion to be formed has a convex shape upward as shown in FIG. The first fixing unit suction surface 302a is arranged in parallel or substantially in parallel with a tangent at the nip outlet of the first heating roller 91a. The distance between the tangent and the fixing unit suction surface 302 is about 0 to 5 mm. The first heating roller 91a and the first pressure roller 91b are in pressure contact with a load of 10 to 80 kgf.

  As described above, according to the fixing unit 90 of the embodiment, it is possible to reduce the influence of the second fixing roller pair 92 on the image surface with a simple structure. Further, according to the image forming apparatus of the present embodiment, it is possible to reduce the influence on the image surface by the second fixing roller pair 92 with a simple structure, and it is possible to form a good image.

  Further, the fixing unit suction in which the end of the suction surface 302 on the second fixing unit side is arranged above the imaginary line connecting the first nip portion and the second nip portion in the conveyance direction of the transfer material S. Since the guide 300 is provided, the transfer material S can smoothly move to the second nip portion of the second fixing roller pair 92.

  Further, since the first fixing unit side of the suction surface 302 is parallel or substantially parallel to the virtual line, the transfer material S can smoothly move to the fixing unit suction guide 300.

  Further, since the first fixing unit 91 side of the suction surface 302 is inclined downward in the vertical direction from the imaginary line, the transfer material S can smoothly move to the fixing unit suction guide 300.

  In addition, the suction surface 302 is formed, the conveyance belt 310 that conveys the transfer material S fixed by the first fixing unit 91, the driving roller 311 that drives the conveyance belt 310 by winding the conveyance belt 310, and conveyance The transfer material S sticks to the fixing unit conveyance belt 310 and the transfer material S and the fixing unit conveyance belt 310 move together, so that the first fixing roller pair The transfer material S can be stably conveyed from the 91 side to the second fixing roller pair 92 side.

  Further, since the fixing unit conveyance belt 310 has the hole 310a through which the airflow passes, the transfer material S can be conveyed more stably.

  10Y, 10M, 10C, 10K ... photosensitive body (latent image carrier), 11Y, 11M, 11C, 11K ... corona charger, 12Y, 12M, 12C, 12K ... exposure unit, 13Y, 13M, 13C, 13K ... first Photoconductor squeeze roller, 13Y ', 13M', 13C ', 13K' ... second photoconductor squeeze roller, 18Y, 18M, 18C, 18K ... photoconductor cleaning blade, 20Y, 20M, 20C, 20K ... developing roller (developer 21Y, 21M, 21C, 21K ... developing roller cleaning blade, 22Y, 22M, 22C, 22K ... compaction corona generator, 30Y, 30M, 30C, 30K ... developing device (developing unit), 31Y, 31M, 31C , 31K ... developer container, 32Y, 32M, 32C, 32K ... anilox Roller (developer supply member), 33Y, 33M, 33C, 33K ... regulating blade, 34Y, 34M, 34C, 34K ... auger, 40 ... intermediate transfer belt (transfer medium), 41 ... belt drive roller, 42 ... tension roller, 45 ... Intermediate transfer belt cleaning blade, 50 ... Primary transfer portion, 51 ... Primary transfer roller, 60 ... Secondary transfer portion (transfer portion), 61 ... Secondary transfer roller (transfer member), 63 ... Concavity, 64 ... Gripper ( Transfer material gripping part), 79 ... Extrusion claw (transfer material peeling part), 85 ... Secondary transfer roller blade, 90 ... Fixing unit (fixing device, fixing part), 91 ... First fixing roller pair (first fixing part) 91a ... first heating roller (first heating unit), 91b ... first pressure roller (first pressing unit), 92 ... second fixing roller pair (second fixing unit), 92a ... first Heating roller (second heating portion), 92b ... second pressure roller (second pressure), 300 ... fixing portion suction guide 302 ... fixing portion suction surface, 310 ... fixing portion conveyor belt, S ... transfer material

Claims (7)

A first fixing unit having a first heating unit that heats a transfer material onto which an image has been transferred, and a first pressing unit that presses the first heating unit to form a first nip unit;
A second fixing unit having a second heating unit that heats the transfer material fixed by the first fixing unit, and a second pressing unit that presses against the second heating unit to form a second nip portion;
The transfer material fixed by the first fixing unit has a suction surface for sucking the image-transferred surface downward in the vertical direction and upward in the vertical direction, and the transfer material is transported in the transport direction of the transfer material. A fixing unit suction guide in which an end of the suction surface on the second fixing unit side is arranged above a virtual line connecting the first nip part and the second nip part;
A fixing device comprising: A latent image carrier on which a latent image is formed;
A developing section for developing the latent image of the latent image carrier with a liquid developer containing toner particles and a carrier liquid;
A transfer medium on which the developed image is transferred to the latent image carrier in the developing unit;
A transfer roller that contacts the transfer medium to form a transfer nip, and transfers the image to a transfer material;
A first heating unit that heats the transfer material onto which the image has been transferred, and a first fixing unit that includes a first pressure unit that presses the first heating unit to form a first nip portion;
A second fixing unit having a second heating unit that heats the transfer material fixed by the first fixing unit, and a second pressing unit that presses against the second heating unit to form a second nip portion;
The transfer material fixed by the first fixing unit has a suction surface for sucking the image-transferred surface downward in the vertical direction and upward in the vertical direction, and the transfer material is transported in the transport direction of the transfer material. A fixing unit suction guide in which an end of the suction surface on the second fixing unit side is arranged above a virtual line connecting the first nip part and the second nip part;
An image forming apparatus comprising:   The image forming apparatus according to claim 2, wherein the first fixing unit side of the suction surface is parallel or substantially parallel to the virtual line.   The first fixing unit is a heating roller in which the first heating unit has an elastic layer, and the first pressing unit is a pressure roller having a surface hardness that is the same as or substantially the same as the surface hardness of the heating roller. The image forming apparatus according to claim 3.   The image forming apparatus according to claim 2, wherein the first fixing unit side of the suction surface is inclined downward in the vertical direction from the virtual line. A conveying belt that forms the suction surface and conveys the transfer material fixed by the first fixing unit;
A driving roller that wraps the conveyor belt and drives the conveyor belt;
A driven roller around which the conveyor belt is wound;
The image forming apparatus according to claim 2, further comprising:   The image forming apparatus according to claim 6, wherein the transport belt has a hole through which an airflow passes.

Images